1. Field of the Invention
This invention relates to a distributor, and more specifically to structural improvements in a distributor which accommodates an angle-of-rotation sensor provided with a magnetic rotating member for detecting angles of rotation of a crankshaft in an internal combustion engine.
2. Description of the Prior Art
Recently, electronic control technology for internal combustion engines has been making rapid progress. With respect to such electronic control, control timing is important and as such it is necessary to detect with precision piston crank angle positions for use as reference signals. Conventional types of angle-of-rotation sensors include, for example, the type disclosed in Japanese Laid-open Patent Publication No. 57(1982)-133311. In this conventional technology a magnetic rotating member is formed by stacking three disk-shaped magnets one on top of the other.
This type of angle-of-rotation sensor is usually accommodated in a distributor, but when the distributor is equipped with an air vent, there is a risk that particles such as of dust and metal, and foreign matter, may enter the distributor via the air vent and adhere to the magnetic rotating member of the sensor, thereby causing changes in the magnetic characteristics of the rotating member that render accurate detection of crank angles impossible.